As evidenced by the recent oil spills in Alaska and the Gulf of Mexico, there is an urgent need to improved techniques for protecting the environment from the spills. Efforts to mitigate the effects of offshore oil spills include chemical dispersion and the use of absorbent pads. Chemicals are sometimes effective to disperse the oil into the water if applied shortly after spill. However, it is not always possible to respond with dispatch because of a variety of reasons, such as the remote location of the spill, lack of chemicals, and weather. Moreover, the long term effects of many dispersants on the ecology have not been fully tested.
If chemical dispersants cannot be used on offshore spills, then the only other remedy to oil spill has been recovery or containment by a variety of mechanical devices, most of which employ some type of absorbent material for separating the oil from the water. Meltblown polypropylene material applied as pads or booms, have received widespread use. The oleophilic property of the polypropylene combined with the microsized fibers of the meltblown web exhibit excellent absorption for the oil. The absorbent pads or booms however suffer from the following disadvantages:
(1) they have low bulk densities (1 to 6 pounds per cubic foot) so that large volumes must be transported to the spill site, presenting a serious logistics problem;
(2) they are cumbersome to deploy (the individual pads are difficult to interconnect); PA0 (3) they are not always suited for land, particularly on irregular terrain. PA0 (a) converting resin to a polymer melt; PA0 (b) delivering the melt to meltblowing die positioned at a remote offboard location; PA0 (c) delivering hot air to the meltblowing die; and PA0 (d) meltblowing the polymer melt from the die by use of the hot air thereby depositing a continuous web onto the surface of the water.
The following patents are representative of polyethylene and/or polypropylene films, sheets and booms used in oil cleanup operations: U.S. Pat. No. 3,146,192; 3,426,902; 3,314,540; 3,259,245, 3,358,838; 3,265,616; 3,215,623; 3,219,190; 3,214,368. U.S. Pat. Re. 31,087 is of particular interest because it discloses microfibrous pads laid on the water to remove oil therefrom.